Magneto cutout mercury switch for tractors



Dec. 21, 1948.. M. J. SMIES MAGNETO CUTOUT MERCURY SWITCH FOR THACTORS Filed Jan. 24, 1947 INVENTOR MELVIN J.SM(ES ATTORNEYS Patented Dec. 21, 1948 UNITED STATES PATENT OFFICE MAGNETO CUTOUT MERCURY SWITCH FOR TRACTORS I Melvin J. Smies, Sheboygan, Wis. Application January 24, 1941, Serial No. 124,101

1 Claim. (Cl. 18082) My invention refers to tractors and it has for its primary object to provide an angular positioned switch tube mounted thereon having an upper and a lower compartment for making and breaking the electric circuit of the spark plugs, the said tube having an intermediate restricted passage forming chambers, the lower chamber being normally filled with mercury while the upper chamber carries terminals of-a ground connection to the spark plug circuit whereby, when the tractor is tilted upwardly and tending to fold backwardly, the spark plug circuit is broken.

It is a well-known fact that tractors traveling over rough ground will develop vibrations, in all directions and these vibrations in ordinary mercury switches will inadvertently make and break the spark circuit. My invention, therefore, is specifically arranged to prevent such minor vibrations from interrupting travel of the vehicle.

The mercury switch'tube is of that general type as is disclosed in Patent No. 2,151,701.

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the novel construction, combination and arrangement of parts", substantially as hereinafter described, and more particularly defined by the appended claim, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claim.

In the accompanying drawings is illustrated one complete example of the physical embodiment of the present invention constructed according to the best mode so far devised for the practicaliapplication of the principles thereof.

In the drawings:

Figure 1 represents a'fragmentary side elevation of a tractor including a spark plug circuit in conjunction with the make and break switch embodying the features of my invention.

Figure 2 is a longitudinal sectional view of the enlarged casing and make and break switch mechanism. v

Referring by characters to the drawings, with specific reference to Figure 2, A indicates a rectangular housing having an inclined wall I therein.

Suitably securedto the wall I, is a non-conducting tube 2 having alower chamber 2 and an upper chamber 2", the tube being closed at its ends.

The upper end of the tube chamber 2" carries a pair of contact wires 3-3', the lower wire being connected by a wire 4, whereby the same is grounded. The wire 3 extends through the housing and is connected to the electric supply wire 5,

2 which wire leads from the magneto post 8 to combined coil box and distributor I, from which coil box distributor wires 8 are connected to the series of spark plugs, as best indicated in Figure 1 of the drawings, it being understood that the diagrammatic electric connections are mounted upon the internal combustion engine B forming part of any suitable type of tractor C.

Referring to Figure 2 of the drawings, the tube 2, intermediate of its length, is restricted to form a narrow supply passa l" between the lower tube chamber and its upper chamber.

When the vehicle or tractor is in its zeneral normal position, it will be noted that the make and break tube is at an-angle of approximately 30 and in said normal position the lower smaller chamber of the tube is completely filled with mercury 9. Hence, in this position, the wire terminals 3 and 3 are disconnected owing to the fact that these terminals are in the empty chamber of the tube. By providing the restricted passage 4", vi-

brations that may occur when the tractor is in its normal position will not cause the mercury 9 to splash upwardly into chamberz", to make and break connections between terminals 3 and 3', which action would tend to ground the electric current intermittently and thereby cause the spark plugs to become inactive.

However, should the tractor tend to rear upwardly, at, for example, an angle of approximately 30, the mercury will fiow from the lower tube chamber 2' through the restricted passage I" into the larger chamber 2" whereby the primary circuit to coil 1 is grounded and the spark plugs are thereby deenergized to prevent further rearing upward or tilting backwardly of the tractor over itsrear wheels. Thus frequent accidents to the driver and injury to the tractor are avoided.

I claim:

In a tractor frame attachment for grounding the ignition circuit system of a tractor comprising a closed horizontally disposed housing secured to the tractor frame upon a horizontal plane, the same being provided with an obliquely disposed wall; a make and break switch comprising an upwardly inclined tube seated upon the obliquely disposed housing wall and interrupted by a restricted passage to form a lower chamber and an .upper chamber, a volume of mercury normally 4 the tractor reaches a sustained elevation of 941- UNITED STATES PATENTS proximately 30".

- MELVIN J. sums. Number Name Date 1,713,191 Penfold May 14, 192. REFERENCES CITED 5 2,151,701 Hudson Mar. 28, 1939 The foilowmg references are of record in the 2.192362, Grlesedleck file or this patent: 

